The Kitten's Nest in the Hellhound's Den
by Takara Phoenix
Summary: ABO-verse with shifters twist - Nico doesn't really know a lot about omegas and their behavior; they didn't talk about those things back in his day. And he's been pretty much packless since he entered the "modern world", only joining their pack at 14. So... it's not really his fault he didn't know it was Percy's nest when he accidentally destroyed it. Nico/Percy slash Nicercy


PJatO || Nicercy || PJatO || The Kitten's Nest in the Hellhound's Den || PJatO || Nicercy || PJatO

Title: The Kitten's Nest in the Hellhound's Den – How Nico Learned a Lesson About Omegas

Fandom: Percy Jackson and the Olympians / Heroes of Olympus

Disclaimer: All rights reserved to Rick Riordan for he created the awesomeness that is Nico di Angelo. And everything else related to Percy Jackson and the Olympians / Heroes of Olympus. Aside from the Gods, they belong to the old Greeks. This fanfiction and its OCs on the other hand are entirely mine. No money is made with this, though reviews are more than welcomed.

Warnings: shounen-ai, ABO-verse, shape-shifters, hurt/comfort, misunderstanding, nesting, fluff, shoujo-ai, hetero, polyamory (threesome)

Main Pairing: Nico/Percy

Side Pairings: Frank/Hazel/Leo, Reyna/Jason/Annabeth

Percy Jackson Characters: Perseus Jackson, Nico di Angelo, Hazel Levesque, Frank Zhang, Leo Valdez, Jason Grace, Reyna Avila Ramírez-Arellano, Annabeth Chase

Summary: Nico doesn't really know a lot about omegas, so how was he supposed to know about nesting, or be able to recognize a nest? After he gets a proper scolding from the omegas in his pack, he has some groveling and begging to do, because Percy nesting in Cabin Thirteen? That sounds really, really, _really_ good once Nico understands what it means.

 **The Kitten's Nest in the Hellhound's Den**

 _How Nico Learned a Lesson About Omegas_

The fact that Nico di Angelo knew nothing about omegas became abundantly clear when he nearly got himself mauled by Annabeth Chase for destroying Percy Jackson's nest.

In Nico's defense, he grew up in the 30s, back when unmated alphas simply didn't have _contact_ with unmated omegas, especially not unchaperoned. The idea of an unmated omega casually hanging out at an unmated alpha's den? Scandalous. And Nico had only been a child, so he had not exactly been taught much when it came to sexuality and behavior – and the past six years in 'modern days', well, four of them Nico had spent in the underworld without a pack and without any unmated omegas in his close proximity. Or any omegas at all, really. Nico had been fourteen when he really joined society, when he really joined a pack. But even at fourteen, he wasn't attending high school or had older siblings or parents who would teach him such social cues.

So, really, it could hardly be considered Nico's fault that he accidentally destroyed Percy's nest. He hadn't known it _was_ a nest. Nico had returned to his cabin that afternoon, as he always did after his sword-fighting lessons. All he wanted was a quick shower – the plus-side of having a cabin that was not expected to host a dozen kids _and_ that got built after the Titan War; Nico got to build a proper bathroom attached to his cabin. But before Nico could even head to the shower, he stumbled over his own clothes. Nico's bed was in one corner of the cabin, with some makeshift walls made of shelves separating Nico's half of the cabin from Hazel's half for some privacy. Now, what Nico was stumbling over were his own clothes, sprawled out in the corner-space between Nico's bed and said makeshift shelf-wall. At first, Nico had frowned confused, before realizing it was most likely Percy's doing. Somehow, the unmated omega was hanging out at Nico's _a lot_. And stealing clothes was a thing Percy also did a lot. With all of his pack. Sometimes, Percy would wear Frank's jacket, or he would wear Reyna's scarf, or Annabeth's hat (granted, that one mostly to play a prank on someone). So finding his closet raided or messed-up was not something new. That Percy would spill all of Nico's closet out on the ground in his search for something specific? New. Still, Nico cleaned it up and then went to take a shower. But when he got out of his bathroom and left his cabin again, he was instantly attacked by Annabeth, who was snarling and feral as she lunged at him.

Which brought Nico back to the right now, where he was back in his cabin, holding a frozen pea-bag against his face while leaning his head back. The problem was, he was surrounded by his alpha friends. Reyna, Hazel and Frank had shadow-traveled here to now look at him pointedly.

"What are you guys doing here?", had Nico asked when they had entered his cabin.

"Oh, we just want our omegas back", had been Reyna's slightly agitated reply. "Because they have been holed up in Cabin Three to comfort Percy ever since _you_ messed up. You messed with an omega's nest? And not just any omega. Percy. Honestly? What is _wrong_ with you, Nico...?"

And that had been that. For the past five minutes, Nico had been mulling this over and holding a bag of frozen peas, courtesy of Hazel who had pressed them into his hand the moment she had stepped through the shadows. Now, Nico was aware he didn't know a lot about omegas, but this?

"What does it mean?", asked Nico reluctantly.

The other alphas seemed startled by this, like they had not expected Nico to reply anything at all. Hazel heaved a deeply disappointed sigh as she sat down next to her brother on his bed. Frank grunted and shook his head, returning to his pacing. Reyna just gave a hopeless sigh.

"You... don't know what it means to mess with an omega's nest?", asked Reyna concerned.

"How?", shrugged Nico with a frown. "I mean, I know... omegas do that. Nesting. But... I always pictured it like... birds do? I don't know. I didn't expect my closet to be abused for that!"

"Oh gods, he's completely lacking fundamental sex ed, isn't he?", muttered Frank in realization.

Realization also dawned on Reyna and she raised both her eyebrows. "Oh dear... Nico..." The Latina took a deep breath and massaged her temples. "Where to start with this one...?"

"How about you explain to me _why_ Percy's nest should be in my cabin?", suggested Nico confused. "I mean, like, I wouldn't mess with his cabin, because I'd expect his den to be where he'd... nest... whatever that means. But... how do _I_ get a black eye out of cleaning up _my own den_?"

There was a long pause in which the other alphas seemed to contemplate on how to explain this to Nico if Nico didn't understand it. Like it was something that was obvious and should be understood.

"Omegas build nests", started Frank awkwardly, fidgeting with his hands. "They do that when their heat is coming up or when they're pregnant. They build nests out of stuff that smells and feels safe. Like, clothes from the pack. It's why Percy, Leo, Jason and Annabeth regularly steal clothes from us all, because we're alphas from their pack and thus, we feel safe. We smell safe."

"Wait. Annabeth is stealing clothes from _me_?", sputtered Nico disturbed.

"Believe me, she's as pleased by that as you are", snorted Reyna and rolled her eyes. "But yes, even to Annabeth, you smell like pack. What? Where... did you think your clothes disappeared to?"

"I figured it was just Percy. He steals clothes from everyone. I figured it was a Percy-thing."

"It's an omega-thing", corrected Hazel with a small, fond look on her face. "It's a Percy-thing to also _wear_ the clothes he's stealing. Leo only uses your clothes for his nest, the only clothes he is wearing are Frank's and mine, if something of mine actually fits him."

"Okay. So... omegas build nests when they go into heat and when they're pregnant. And they build their nests out of stuff that smells like pack", summed Nico up slowly. "But that still doesn't explain why Percy would build his nest in _my den_. Back in my day, an unmated omega would never even dare to enter an unmated alpha's den. Why would Percy build his nest in my den?"

"Really?", asked Reyna slowly, both eyebrows raised, just to sigh when Nico still stared at him completely lost. "Omegas build their nests in their own dens normally, yes. Unless they have mates or are courting. Then they build their nests in their mates' dens, because the additional protection of it being their alphas' den is even better. Now, think long and hard on what that might mean."

"...Percy... isn't my mate. We're not courting", supplied Nico confused, frown on his face. "Wait. D—Do you mean... Do you mean Percy _wants_ me as his alpha...?"

"Yes", groaned Frank, throwing his head back. "Finally. Seriously, you're the last one to notice."

"I... But... But he didn't... say anything?", frowned Nico, confusion steadily growing.

"He built his nest in your den. That's... That's him telling you", replied Hazel, eyes soft. "Granted, unlike you, we all caught on with our omegas' interests before their heat came up. But Leo? He built his nest in mine and Frank's bedroom when he wanted to tell us that he wanted us as his mates."

"Jason came home from his mission of building temples and when his first heat hit, he built his nest in the praetors' house, even though he's not praetor anymore", added Reyna gently. "And when Annabeth finished her plans for her camp, when she built the Enyo Cabin specially for me, to welcome me to Camp Half-Blood, she built her nest in it to show me that the cabin was not just an act of friendship, that what we had built over the months after the war was more."

"...And... what does it mean that I... that I destroyed his nest?", asked Nico, voice small.

"In general, an omega who builds their nest in an alpha's den is _very_ sure that their feelings are reciprocated. It's really an act an omega would only do when there is no possible way the alpha would decline the invitation to courting. And with... your years long track-record of being in love with him, there really was no reason for Percy to believe you would not want to court him. There _are_ more subtle ways to invite an alpha to courting", started Hazel slowly. "But to destroy an omega's nest? That's... the hardest no you could give him. It's..."

"It's kind of like saying 'How dare you even _think_ I would pick you!'...", supplied Frank bluntly.

"Which is why Annabeth attacked you", added Reyna, gently tracing Nico's black eye. "Percy is like her little brother and you... really hurt him, even if it was by accident, Nico. All she saw was an alpha who hurt her brother. You... You will have to work hard for that one, not gonna lie, but... it was an honest mistake and if you explain it to Percy..."

Nico heaved a shaky breath and collapsed back against his bed. A lot of hard work, huh?

/break\

Percy mewled miserably where he was curled together very small in a hastily made makeshift nest, a messy thing that he had only managed to throw together so fast thanks to his friends. He honestly didn't know what he'd do without Annabeth in his life. She instantly called the Romans and with Mrs. O'Leary, Leo and Jason were right away ready to supply warmth and comfort and safety for Percy, who was in dire need of pack comfort. Percy was shifted, only a tiny black little ball of fluff in his cat-form, with the white wolf-form of Jason curled around him, Annabeth as a snow owl nestled between them, having one wing spread out safely over Percy, all three of them surrounded by Leo whose dragon-form was only a bit larger than Jason's wolf.

When the day had started, Percy had been positive that it was going to be a good day. A really good day. Two years ago, when the Giant War had ended, Nico had awkwardly confessed to him. Back then, romance was the _last_ thing on Percy's mind. He had a severe case of PTSD and depression to deal with after the two wars and he had never really contemplated Nico as a viable romantic interest. But over the past two years, Percy had now finally finished high school only weeks ago, he had opened up a PTSD support group, had countless sessions with Psyche, who apparently doubled as a psychiatrist for the heroes since demigods could hardly go to a regular psychiatrist with their issues. Percy was on a good track. He was going to start college this fall, in New Rome. New Rome was going to be the beginning of a new chapter in his life and Percy really wanted Nico in that chapter, as more than just a friend. Over the past two years, Percy had grown more than just fond of Nico and in the past few months, Percy had spent a lot of time thinking about Nico as more than just an alpha in his pack but as _his_ alpha. Percy had it on pretty good authority that Nico's feelings for him, despite the long time, had never subsided. That Nico still loved him. So, since Percy planned on moving to New Rome, he had thought he would put all of his cards on the table and make Nico his. His heat was coming up and it was the perfect opportunity. While Nico was out going through his classes for the day, Percy had sneaked into Cabin Thirteen and started building his nest. He had only left it for ten minutes or so to go and already get some provisions to store in the cabin, but when he returned, his nest had been taken apart and Nico had been in the bathroom. Nico didn't even take the time to say it to Percy's face, that he wasn't wanted.

" _It's going to be alright_ ", cooed Leo softly, gently licking Percy's cheek.

The kitten meowed and shook his head, tiny face buried in the soft underbelly of Jason, with the wolf's strong paws wrapped around him protectively. Jason was nudging Annabeth softly, looking at her with concerned eyes. The two had started out with quite the rivalry, when Jason had come to camp as a kind of replacement for Percy, it had pissed Annabeth off, then they met the Romans and Jason, he remembered Reyna, remembered the alpha he wanted, while Annabeth was instantly enthralled with Reyna the first time those two walked the streets of New Rome together. So their rivalry grew. Reyna? Reyna really liked both stubborn, strong, pretty, blonde omegas. They worked something out and Jason and Annabeth had grown more than just fond of each other. They might not love each other the way they both loved Reyna, but they shared more than friendship.

" _I will claw the death mutt's eyes out_ ", growled Annabeth, feathers flaring up.

" _You will do no such thing, Annie_ ", chided Jason, nosing her cheek. " _Rey said she'd talk to him. Let's wait out Percy's heat and then hear what our alpha found out_."

" _Yeah. Good plan. Hazel and Frank will talk some sense into him too_ ", agreed Leo.

Percy just hid his face between his paws. He didn't want to see anyone or think of anyone, much less Nico. He just wanted for his heat to start, get over and then he wanted to move maybe to Alaska. Or any other place far away from Nico so Percy would never have to think about that embarrassment. He had made such a fool of himself. Who did he think he was? That Nico, after already having been in love with Percy for so long, would still stay in one-sided love with Percy for _two more years_? Of course he had moved on. Why would he still love Percy...?

/break\

Nico was nervously pacing in front of Cabin Three, with Frank, Hazel and Reyna sitting at the stairs and watching him. The three mated alphas had heard from their omegas on multiple occasions during the past weekend of Percy's heat. The other three omegas did not let Nico close, which was only fair because unmated alphas really shouldn't be close to an unmated omega in heat, especially not when that omega didn't _want_ them close. Which Percy, quite clearly, didn't want at the moment. Even Jason, who was Nico's friend more so than Leo or Annabeth, had given him a nasty glare the last time the omegas had emerged to get some more water and provision.

The door opened. It had taken three days and finally, the door opened as Percy's heat was finally over. Nico froze on the spot and stared over at the door hopefully. Annabeth was the first one to exit the cabin and when she saw Nico, she snarled at him and was ready to lung at him again. Jason held her back by the wrist and Reyna stepped between Annabeth and Nico.

"Hello, love", smiled Reyna gently, cupping Annabeth's face. "I missed the both of you. You two reek of Percy. How about we go to Jason's cabin and you two... take a nice, long, hot shower?"

"Shower sounds good, Annie", hummed Jason, gently nuzzling the other blonde. "Come on."

"I am _not_ leaving Percy alone with _him_ ", growled Annabeth protectively.

"They're not alone", promised Hazel as she stepped up behind Annabeth. "We'll stay, okay? Leo will stay. But you're... you're taking this far too personal, Annabeth. You need to cool down. I understand you, I do. I would rip the world apart if someone hurt Nico, but... Nico didn't do this on purpose. Him and Percy both deserve the chance to talk this out. And even though I promise you that Nico didn't do it on purpose, me and Frank will still stay around and make sure my brother won't do anything else to hurt Percy. We will, okay? And if Nico does something stupid, Leo will set him on fire, won't you, firebug?"

"Pro—omise", chimed Leo where he was happily snuggled up to Frank's lap. "To a crisp."

Annabeth frowned for another moment and searched for Percy's eyes. Only when the son of Poseidon nodded sharply did Annabeth sigh in defeat and allow Reyna and Jason to pull her along.

"If you hurt him again, di Angelo, I will _gut_ you with my talons", was her last warning.

With them out of the way, Nico had clear view on Percy. His heart sank. Percy looked beaten. His hair was ruffled and looked a bit like straw, there were bags beneath his eyes, his eyes themselves kind of dull. He was _hunched over_. Percy Jackson did not hunch over. For no one. He hadn't cowered in front of gods and titans and giants. Yet here he was, cowering in front of _Nico_. Nothing had ever broken Nico's heart that badly, not even the fear of being rejected by Percy – he had rejected Percy, he had hurt Percy, he had made Percy feel like that. _He had done this_.

"P—Perce...", started Nico, voice breaking off.

"I'm sorry", whispered Percy, very decidedly not looking at Nico.

"...Huh?", grunted Nico confused, blinking at the son of Poseidon.

"I'm sorry for building my nest in your cabin", elaborated Percy, voice so soft, it was barely audible, eyes trained on his own hands. "I... It was self-centered of me to assume you still have feelings for me. I shouldn't have. Of course you don't. I'm sorry."

"What? I—No!", exclaimed Nico stunned and leaped forward to grasp Percy's face very gently and tilt his head up so the omega would finally look at him. "I love you. I love you so, so, _so_ much, Percy. I never stopped loving you. I don't think I ever will stop loving you."

"...Then... why?", asked Percy, staring at Nico with a reluctant, unsure frown.

"I didn't know. I—I don't know _anything_ about omegas. I never learned it. I was still a child when I lost my family, when I lived in the underworld. I joined this pack two years ago, when I was fourteen, when most of you already had your basic education about secondary genders. I just... back in my time, we were taught not to ask such things. They were private. They weren't an alpha's business. I... I thought you just made a mess when rummaging through my closet. I didn't...", started Nico frantically, practically clinging onto Percy. "I swear I had _no idea_ what it meant. I would have never destroyed your nest if I had known it was a nest. I swear, Percy, please. Please give me another chance. Please, I beg you. I'll do better. I—I'll take, I don't know, classes from Will, even though I will die of embarrassment, but I never want to accidentally hurt your feelings like that again, because I love you, Percy. I really do. You're the... the only omega I'd ever want to be with."

Percy stared at Nico with a calculating, contemplative look before heading back into Cabin Three.

/break\

Four weeks, including the move from New York to New Rome, that was how long Percy let Nico prove himself. For four weeks, Percy made Nico work hard to earn his trust back.

Granted, Annabeth made that hard for Nico, but she was such a big support for Percy. Jason, Reyna and Annabeth decided to spend the summer at Camp Half-Blood as moral support, though Percy knew that Reyna was mainly there for Nico. Percy knew Reyna was the one showing Nico the ropes of how to be a proper alpha and how to court an omega. After all, she had successfully courted two omegas. And Jason and Annabeth all the while supported Percy.

Jason was very strongly pro-Nico, while Annabeth was very strongly anti-Nico. The two blonde omegas were very nearly literally Percy's angel and devil on his shoulders. But it was also what he needed. Percy didn't want to be blinded by his love for Nico, he didn't want to instantly forgive Nico just because the son of Hades begged for forgiveness. It was the reason Percy had walked away from Nico before he could fall into the alpha's arms and forgive him.

Annabeth helped Percy stay strong. It had been Jason's suggestion to make Nico work for it by courting – and Nico had been more than eager and grateful to accept that second chance.

Every single day, Percy would find a small gift in front of his cabin's door. A single, blue-dyed rose, a blue cupcake, blue chocolate, a piece of jewelry, a cute stuffed toy, something self-made, even a poem once or twice. It was endearing and sweet. Percy _loved_ it. Nico also did sweet things for Percy, like pull his chair back for him or polish Percy's armor for him or taking Mrs. O'Leary on a walk for Percy when Percy was too exhausted after a long day of camp.

Nico had helped Percy pick out an apartment in New Rome, together with the rest of the pack. Only, what Nico didn't know was that his opinion weighed heavier than that of the rest of the pack because Percy planned on living here with his alpha. After all, Nico was being so damn cute while courting Percy and while doing everything in his powers to prove to Percy that he valued the son of Poseidon and that he was sorry – he _still_ regularly apologized, which was actually getting kind of exhausting if Percy was being honest. No, it was really clear that Nico had made an honest mistake, that Nico hadn't destroyed the nest because he was disgusted by the idea of being Percy's mate.

Yet still, Percy let Nico continue working for it. Percy wanted to do this right, he also wanted to do this once they'd move to New Rome, which was right now. It was only when Nico obediently shadow-traveled the last of Percy's things into the new apartment that Percy grabbed the alpha and pulled him into a brief kiss, startling him so Nico dropped the box.

"You know you're moving in with me, right?", whispered Percy softly against Nico's lips.

"I—I... what?", stuttered Nico, face flushed a bright pink. "B—But..."

"You've... been nothing but a considerate gentleman the past four weeks. You courted me by all the rules of the book. You did take those classes from Will and left every single one with ruby-red ears. You've been apologizing to me every single day", whispered Percy, gently caressing Nico's cheek. "I didn't believe you at first, but... you proved it to me. That you didn't mean it. That you love me. And I believe you. I love you, Nico. I... still want you too, Nico."

"Really?", asked Nico hopefully, giving Percy a very convincing puppy-pout.

"Yes, really", laughed Percy softly, wrapping both his arms around Nico's neck to pull the alpha down. "You... You were so convincing, even Annabeth stopped snarling at you all the time. I love you, I really do. I want this to be the start of a new chapter, for the both of us. I want to... to leave that misunderstanding behind, I want a new start here. If you want to."

"Yes", blurted Nico out, hastily laying his arms around Percy's waist to hold him close. "I... You were the only reason I was still at Camp Half-Blood. My two best friends and my sister are all living in New Rome, but... I didn't want to leave you alone, not while you were still stuck in high school in New York. I would... I would love to live with you, Perce."

"To prove yourself further", interrupted Percy firmly. "We're going to do that... boyfriend-thing. Living together. Being together. And then, let's see how it goes, we'll bond. That... okay?"

"That's... That's... yes", nodded Nico hastily, smiling in a dopey way as he was kissed deeply. "But we have to go back and get my stuff now, right?"

"There... is something I wanted to do for a month now...", drawled Percy with a flush. "Can we... do that first, before we get your stuff? Because after bringing all my things here and after building our furniture all morning... I'm really exhausted. So... can I have... alpha-cuddles?"

The dopey grin on Nico's lips grew even more as he shifted. Percy cooed just a little when that endearingly faithful looking hellhound stared up at him with a wagging tail. Then, Percy also shifted. It was kind of ridiculous, because Percy was about the size of Nico's head. But the hellhound was very gentle as he curled together around Percy. He was also very warm and comfortable, mused Percy as he curled together against Nico's soft underbelly. It felt far safer and warmer than pack-cuddles, just knowing that this was going to be _his_ alpha. He meowed happily as he licked Nico's cheek, making the hellhound whine contently.

 _~*~ The End ~*~_

* * *

 _Author's note: With my Alphas of Percy Jackson series, I've been writing so many alphas with Percy by now that I was craving some Nicercy again. So I handed kitten!Percy over to hellhound!Nico. I'm also a huge fan of the alpha accidentally messing with the omega's nest and having to make up for it, including all the feels in entails. Hope you guys had fun with it too ;)  
_


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